1. Technical Field
The invention relates to the technical fields of a method and an apparatus for manufacturing a slip stopper employed for a construction machine, such as a hydraulic excavator, or other surfaces that need to be non-slip.
2. Background Art
Generally, a slip stopper with a slip stopping function is occasionally used for floors, passageways, and stairs in building structures, floors and steps of buses, trucks and special vehicles, decks of railroad vehicles and ships, and scaffolding at construction sites. Such a slip stopper, for example, as shown in FIGS. 10(A)–10(C), has been conventionally known. This is a so-called striped steel plate that has a plurality of projections 51 molded in continuous patterned shape, and a corresponding slip stopping effect can be expected in the case of normal scaffolding. However, the height of the projections 51 of this striped steel plate is low and curved, so that a more reliable slip stopper is required when workers step on a cover covering the upper surface of a construction machine as a stepping surface during maintenance.
Therefore, as shown in FIGS. 11(A)–11(B), a slip stopper for construction machines has been provided in which slip stopping parts 53, having raised edges formed by the marginal portion of a through hole 52 stamped out into a circle shape or a star shape, are formed in a running pattern. In this slip stopper, the raised portions of the slip stopping part 53 can be made sufficiently high, and sharp shear planes are formed by means of the stamping-out process, so that a great slip stopping effect can be obtained.
If the slip stopper having the through hole stamped out is used as it is as a cover to cover the upper surface of a construction machine, problems, such as rainwater or dirt entering the inside of the cover, heated air from an engine blowing upward from the cover, or noise diffusing, are inevitable. Therefore, a double structure in that a flat steel plate is fixed to the lower side of the slip stopper is employed to prevent the abovementioned problems. However, the double structure increases production processes and costs in comparison with the single structure and, further, poses a problem in that mud or dust entering through the through hole of the slip stopper accumulates between the slip stopper and the lower side flat steel plate or in the through hole, and makes cleaning difficult. These problems are solved by the invention.